Heat-insulated container

ABSTRACT

The present invention relates to a thermally self-insulating container ( 1 ), preferably a “bottle,” “flask,” “can,” or the like, designed to directly receive a product, preferably a food product such as a beverage, introduced or extracted, by means of an opening ( 5 ) closed by a cap ( 6 ), into or from an interior ( 4 ) delimited by an inner wall ( 2 ), said container also comprising an outer wall ( 3 ), which with the inner wall delimits a closed chamber ( 24 ), most of said inner wall ( 2 ) having a first state of high thermal conductibility and a second state of low thermal conductibility. Such a container is characterized in that it comprises intrinsic transformation means and mechanical control means (R) for switching from said first state to said second state. The invention can be applied to the thermal insulation of beverages to be consumed hot or cold.

[0001] The present invention relates to a thermally self-insulating container, particularly a bottle, flask, can or the like, designed to receive a product, preferably a food product, for example a beverage.

TECHNICAL FIELD OF THE INVENTION

[0002] The principle of a double wall for limiting heat exchanges between the interior and the exterior of a container—or vice versa—has been known for quite some time. The Dewar's flask, which comprises two walls that are silvered on the inside, between which a vacuum is produced, eliminates any possibility of a thermal transfer by conduction, convection or radiation. This type of container, invented by the nineteenth-century English chemist and physician for whom it is named, is the ancestor of all the thermally insulated containers known today as “thermos bottles.”

[0003] However, thermoses are fragile, and therefore, in order to avoid this drawback, it is common to replace the existing vacuum between the two walls with a material of low heat conductivity, in order to improve the strength of the double wall.

[0004] In this respect, as shown in particular by U.S. Pat. No. 2,215,532 granted on Sep. 24, 1940 in the name of E. Richardson, the use of a thermally insulating fluid is not novel. The method and device described also provide a solution to the problem of reheating an insulated container, which consists of precisely controlling the convection movements of the fluid inside the wall.

[0005] The issue of allowing thermal exchanges between the environment and the container's interior and of insulating the latter as needed can be important, for example in the sale of beverages that must preferably be consumed hot or cold, each at a so-called ideal temperature. This requires efficiently heating—or cooling—the beverage to said ideal consumption temperature inside its container, then maintaining it at this desired ideal temperature until the moment it is consumed, said beverage then being insulated or, in other words, the container then no longer being subject to a thermal transfer from its environment, in order to maintain the beverage at the ideal consumption temperature.

[0006] To this end, the thermal properties of the wall of the container can be adapted to various conditions of use through the appropriate choice of its structure and of the nature of the fluid.

[0007] For example, French patent application 2,306,661 published on Nov. 5, 1976 in the name of M. Brevi describes a cooling glass beverage container whose structure is that of a Dewar's flask, but whose vacuum has been replaced by water that can be frozen. According to the inventor, the ice formed makes it possible to cool the beverage contained in the glass, while remaining insulated from the ambient temperature.

[0008] Japanese patent application 10,099,213 published on Apr. 21, 1998 in the name of the company Yokohama, describes a beverage container that uses a similar principle. Ice water can be introduced inside the double wall, through the removable bottom of the container, and can be changed as needed.

[0009] Part of the wall of the container can be changed from a state of low heat conductibility to a state of high conductibility simply by removing the insulating material. European patent application EP 0 891 738, published on Jan. 20, 1999 in the name of D. Bengston, illustrates this type of method; the conductive base of the thermos bottle is provided with a removable insulating cover.

[0010] Using a gas with low thermal conductibility as the fluid has also given rise to a large number of thermally insulating devices.

[0011] One of the simplest systems, for example described in U.S. Pat. No. 5,896,641, published on Apr. 27, 1999 in the name of M. Yamada et al., comprises a chamber filled with xenon, krypton or argon gas, introduced inside a double wall.

[0012] The insulating chamber can also be just a flexible inflatable structure. German patent application 3,813,218, published on Nov. 2, 1989 in the name of the company H & V Konzeption Design Planung, illustrates such a design. The container, designed to protect foods or beverages and keep them cold, is constituted by two sheets of flexible material, PVC or the like, joined to one another to form chambers inflated by means of a valve.

[0013] Other devices based on the same principle use a compressed gas generator to inflate the walls of the container. Japanese patent application 5,278,765, published on Oct. 26, 1993 in the name of the company Fushimi Jushi, discloses the use of a carbon gas cartridge.

[0014] The phenomenon of the liquefaction or vaporization of a fluid at a given temperature can be applied to the production of insulating walls at high temperatures. In fact, above its vaporization temperature, the fluid is in a gaseous state of low conductibility, whereas below that point it is liquid and therefore transmits heat better. For example, the walls described in Japanese patent application 7,156,974, published on Jun. 20, 1995 in the name of the company Kukoba, undergo a change in their thermal properties between 300° C. and 400° C.

[0015] In the case of a package for foods intended to be heated in a microwave oven, as described in U.S. Pat. No. 5,081,330, published on Jan. 14, 1992 in the name of L. Brandberg et al., the expansion of the residual air present between two sheets of material joined along lines of contact is enough to create insulating chambers.

[0016] All of the documents described above refer to or disclose a device for modifying the heat conductibility of the walls of a container. This modification is obtained by either adding or removing an element of the container, or by modifying the temperature outside it. But none of these systems, methods and/or devices contained in the prior art uses internal means integrated into the container to achieve the transformation. Moreover, the existing thermally self-insulating containers do not, in general, provide a solution to both the problem of heating, and the problem of cooling, an insulated container.

[0017] It is clear from the prior art that there are known thermally self-insulating containers comprising a double wall whose gap contains a fluid, and having two states, insulating or conductive, but that to date, there is no existing device that precisely meets the stated needs.

GENERAL DESCRIPTION OF THE INVENTION

[0018] The subject of the present invention is a thermally self-insulating container, preferably a “bottle,” “flask,” “can,” or the like, designed to directly receive a product, preferably a food product such as a beverage, introduced or extracted, by means of an opening closed by a cap, into or from an interior delimited by an inner wall, said container also comprising an outer wall, which with the inner wall delimits a closed chamber, most of the inner wall having a first state of high thermal conductibility and a second state of low thermal conductibility, said container being characterized in that it includes transformation means that are intrinsic to it, and mechanical control means for switching from said first state to said second state, and in that, in the first state, the chamber delimited by the double wall comprises a thermally conductive liquid that fills at least the part of said chamber that is located level with the interior, and in that, in the second state, the chamber delimited by the double wall contains a thermally insulating gas that fills at least the part of said chamber that is level with the interior.

[0019] Advantageously, the thermally conductive liquid and the thermally insulating gas present inside the double wall are preferably water and air, respectively.

[0020] According to two first variants of embodiment, the self-insulating container according to the invention is characterized in that the chamber delimited by the double wall:

[0021] a) contains a first fluid with high thermal conductibility and a second fluid with low thermal conductibility, said first and second fluids having different volumetric masses and being non-miscible with one another,

[0022] b) has a dissymmetry such that, in a first position of the container corresponding to the first state, most of the inner wall is wet with the first fluid, and in a second position of the container corresponding to the second state, most of said inner wall is wet with the second fluid.

[0023] In a first variant of embodiment, the thermally self-insulating container according to the invention is characterized in that the dissymmetry results from a space between the part of the outer wall that constitutes the base of said container and the part of the inner wall opposite this base, the volume of said space being greater than 50% of the total volume of the chamber delimited by the double wall.

[0024] In this first variant of embodiment, the container according to the invention is preferably always such that:

[0025] a) the first fluid is a liquid with high thermal conductibility, preferably water, and the second fluid is a gas with low thermal conductibility, preferably air,

[0026] b) the first position of the container corresponding to its first state is a first vertical position, the opening or neck being headed downward, and the second position of the container corresponding to its second state is a second vertical position in which the opening or neck is turned upward.

[0027] In a second variant of embodiment, the thermally self-insulating container according to the invention is characterized in that the dissymmetry results from a thickness of the chamber delimited by the double wall that is greater at the level of a part of the inner wall that constitutes a side of the container than it is at the level of the diametrically opposed part of the inner wall.

[0028] In this second variant of embodiment, the container according to the invention is always preferably such that:

[0029] a) the first fluid is a liquid with high thermal conductibility, preferably water, and the second fluid is a gas with low thermal conductivity, preferably air.

[0030] b) the first position of the container corresponding to its first state is a first horizontal position in which the part of the chamber delimited by the double wall having the greater thickness is located at the top of the container, and the second position of the container corresponding to its second state is a second horizontal position in which the part of the chamber delimited by the double wall having the greater thickness is located at the bottom of said container.

[0031] According to a third variant of embodiment, the self-insulating container according to the invention is characterized in that the transformation means comprise a breakable membrane placed between the part of the outer wall that constitutes the base of the container and the part of the inner wall opposite this base, and designed to release by gravity the overlying thermally conductive liquid, as well as a thermally insulating gas, preferably air, that fills the space between said membrane and the part of the outer wall that constitutes the base of the container.

[0032] In this third variant, the control means with which the container according to the invention is equipped preferably comprise means for breaking the membrane, preferably by impact or by pressure.

[0033] Advantageously, in all of the variants envisioned, the double wall of the container according to the invention is made of plastic or aluminum or any other material compatible with the product to be thermally insulated.

[0034] Equally preferably, in all of the variants envisioned, the container according to the invention is always such that its first and second fluids are permanently introduced into the chamber delimited by the double wall during the production of said container.

BRIEF DESCRIPTION OF THE DRAWINGS

[0035]FIGS. 1a and 1 b are schematic sectional views of a first embodiment of the thermally self-insulating container according to the invention, wherein the wall is respectively in a state of high thermal conductibility and in a state of low thermal conductibility after the righting of the container within a vertical plane.

[0036]FIGS. 2a and 2 b are schematic sectional views of a second embodiment of thermally self-insulating container according to the invention, wherein the wall is respectively in a state of high thermal conductibility and in a state of low thermal conductibility after a horizontal rotation of the container by one-half turn.

[0037]FIGS. 3a and 3 b are schematic sectional views of a third embodiment of the thermally self-insulating container according to the invention, wherein the wall is respectively in a state of high thermal conductibility and in a state of low thermal conductibility after the rupture of an internal membrane.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0038] The present invention consists in a container (1) with a double wall, each of said walls (2, 3,) being impermeable. The inner wall (2) delimits a closed interior (4), designed to receive a product, preferably a food product, which throughout the description below will be defined, by way of example, as a “beverage.” The top part of this inner wall (2) which is either flat if the container is a type of “can,” or neck-shaped if the container is a type of “bottle” or “flask,” as shown for example in the drawings, comprises an opening (5), which is closed by a cap (6), and through which the beverage is introduced into the interior (4). The outer wall (3) is connected to this inner wall (2) at the level of the opening (5), or slightly beyond it. The connection between the two respective inner (2) and outer (3) walls, is itself impermeable. The walls (2, 3) thus delimit between them a chamber (24) that is itself closed.

[0039] The particular shape and position of the interior (4) relative to the outer wall (3) allow the transformation from a thermally conductive container to a thermally insulated container through a simple change in its position.

[0040] A first preferred embodiment of the container is represented schematically in FIGS. 1a and 1 b. In this first embodiment, the walls (2) and (3) are separated from one another by a gap (A) that is constant at the level of the sides of the container, but it is provided for a distance (B) wider than the aforementioned gap (A), visible in FIGS. 1a and 1 b, to separate the bases (22, 23) of the respective inner (2) and outer (3) walls. (It should be noted here that, for a better understanding of the drawings in FIGS. 1a and 1 b, the gap (A) that separates the walls (2) and (3) has purposely been widened.)

[0041] This wider distance (B), moreover, is such that the volume of the space (11) located between the two bases (22, 23) is greater than 50% of the total volume of the chamber (24) delimited by the two walls (2, 3).

[0042] In FIG. 1a, the container (1) is represented with its opening (5), in this case its neck, headed downward. In this position, the double wall (2, 3) is partially filled with a liquid having high thermal conductibility (9), which has been introduced into the chamber (24) delimited by the walls (2, 3) until it covers at least the base (22) of the inner wall (2). The wall (2) at the level of the neck and sides of the interior (4) thus allows thermal transfers with the outside in order to heat, cool, or maintain at an adequate temperature—i.e. the ideal consumption temperature—the beverage contained in the interior (4) of the container (1).

[0043] Advantageously, the volume of the thermally conductive liquid (9) occupies less than 50% of the total volume of the chamber (24), and preferably a volume slightly less than 50% of the aforementioned total volume.

[0044] Consequently, above the base (22) of the interior (4), there is a subsisting space (11) in the chamber (24) delimited by the two walls (2, 3), that is empty of liquid and filled with insulating gas (10), which itself consequently occupies a volume greater than 50% of the volume of the thermally conductive liquid (9).

[0045] Thus, the space (11) has enough volume to collect at least the total amount of liquid (9) contained in the double wall (2, 3) when the container (1) is vertically returned (R) to the normal position with its neck (5) heading upward. This position is represented in FIG. 1b. After such a return, the interior (4) is then totally surrounded by the gas (10) and the thermal exchanges with the environment are considerably limited.

[0046] The gas (10) and the liquid (9) used are preferably air and water, respectively.

[0047] Air is actually a good enough thermal insulator because it has a thermal conductibility coefficient of 0.025 W/m° K, while that of water is about 20 times greater.

[0048] A simple calculation makes it possible to estimate the thickness that must be given to the layer of air (the above-mentioned gap (A) separating the walls (2, 3) at the level of the sides of the container) in order to maintain, for a duration D, a cylindrical container containing water below a certain temperature T₁, the container having been cooled to the temperature T₀ and the ambient temperature being T_(amb), taking into account only the thermal exchanges through the lateral surface of the container (1) and ignoring exchanges by convection and radiation.

[0049] For an initial temperature T₀=5° C. and maintenance below T₁=10° C., the results are as follows (the thickness or gap (A) in mm), in the case of a cylinder having a diameter of 90 mm (the size of a standard 1.5-liter bottle of mineral water): T_(amb) Time 20° C. 25° C. 30° C. 35° C. ½ H 2 2 3 3 1 H 3 4 5 6 2 H 5 7 9 11 4 H 10 14 18 22

[0050] The thickness (A) that must be given to the double wall (2, 3) being known, it is easy to deduce from it, in the case of a cylindrical container with a volume of 1.5 L, the minimum height (B) of the space (11) for receiving the thermally conductive liquid after the return (R). An elementary calculation shoes that the relative increase in the height of the outer wall (3) must be approximately equal to double the relative increase in the radius of the inner wall (2), in other words, the relative thickness of the double wall (2, 3). Under the same temperature conditions as before, the approximate additional minimum height (B) to be provided (in mm) is: T_(amb) Time 20° C. 25° C. 30° C. 35° C. ½ H 20 20 30 30 1 H 30 40 50 60 2 H 50 70 90 110 4 H 100 140 180 220

[0051] These results show that, given an outer wall (3) with dimensions slightly larger than those of the non-insulated container, the beverage contained in the interior (4) remains cool for a considerable duration, even if the ambient temperature is high.

[0052] The effect of the insulation is of course the same, whether the beverage is hot or cold. Thanks to the remarkable simplicity of the device, it is even possible for the vendor to present the container according to the invention to his customer in a normal position, and the container still retains an optimal temperature for a long time.

[0053] In the second embodiment of the self-insulating container according to the invention, represented schematically in FIGS. 2a and 2 b, the principle of creating a dissymmetry in the internal volume of the double wall (2, 3) is used again. The dissymmetry in this case is axial; two diametrically opposed lateral walls of the double wall (2, 3) have different thicknesses.

[0054] The dissymmetry being axial, the container must be lying down in order for it to produce a variation in the position of the liquid (9) inside the double wall (2, 3) when the container (1) is turned over by a half-turn (R).

[0055] When the part having the smallest thickness is located at the bottom of the container, as shown in FIG. 2a, a given volume—here again less than 50% of the total volume of the chamber (24)—of the liquid (9) must cover a large surface area. Most, if not all, of the interior (4) is therefore surrounded by a wall (2) with high thermal conductibility. The opposite is true when the part with the greater thickness (11) is at the bottom of the container (1), as shown in FIG. 2b; this part (11) collects the liquid (9), and the gas (10) therefore insulates the interior (4).

[0056] The change from the most conductive state to the most insulating state is, here again, produced manually by a 180° rotation (R) about the axis of the container (1).

[0057] In an advantageous method of production, the fluids (9, 10) are introduced permanently. For this purpose, the outer wall (3) comprises one or two orifices (7) near the neck (5) and provided with closures.

[0058] In certain cases, the user will find it preferable to periodically change the thermally conductive liquid (9), particularly if it is water. One of the two orifices (7) makes it possible to extract water from, then introduce it into, the chamber (24) delimited by the double wall (2, 3). The identical second orifice (7) allows the simultaneous evacuation of the air. The orifices (7) are closed after this operation.

[0059] However, the orifice (7) may be the only one and may allow the opposing and simultaneous movements of the water (9) and the air (10) if it is of sufficient size for this purpose.

[0060] In the third embodiment schematically represented in FIGS. 3a and 3 b, the outer wall (3) comprises two orifices (7, 8) that are near the neck (5) and are provided with closures. A membrane (12) is placed between the part of the inner wall (2) that constitutes the base (22), and the base part (23) of the opposing outer wall (3).

[0061] One of the orifices, for example the orifice (7), makes it possible to introduce into the internal chamber (24) of the double wall (2, 3), located above the membrane (12), a thermally conductive fluid (9). The second orifice (8) allows the evacuation of the air. The orifices (7, 8) are closed after this operation.

[0062] The part (13) of the chamber (24) between the membrane (12) and the outer base (23) of the container (1) opposite the membrane (12) remains filled with air.

[0063] As seen above in connection with the first two embodiments of the invention, the volume of the part (13) of the chamber (24) originally filled with air is greater than 50% of the total volume of the chamber (24) and hence greater than the volume of the part of said chamber located above the membrane (12).

[0064] Most of the double wall (2, 3) filled in this way has a high thermal conductibility that encourages heat transfers between the interior (4) and the environment. The beverage can therefore be easily heated, cooled, or maintained at the appropriate temperature, i.e., the ideal consumption temperature.

[0065] At any time, the membrane (12) can be broken, as shown in FIG. 3b, and the thermally conductive fluid (9) flows by gravity into the space (13) located below, while the air (10) replaces it in the part of the double wall (2, 3) located level with the interior (4).

[0066] Under these conditions, heat exchanges between the beverage and the outside are limited, and said beverage consequently retains its optimal temperature.

[0067] Advantageously, these “mineral water bottle,” “soda bottle,” “beer can,” or “flask” type containers are made of plastic or aluminum or any other material compatible with the product to be thermally insulated.

[0068] The following is a nonlimiting list of examples of products that can be contained in a container according to the invention:

[0069] water, which may or may not be mineral water and may or may not be carbonated, milk and other liquid or solid milk-based foods, tea-, coffee- or chocolate-based beverages, soups and broths, sodas, fruit juices, beer, carbonated soft beverages, wine, alcohol such as vodka, in terms of food products,

[0070] blood, in terms of a non-food liquid,

[0071] organs for transplant.

[0072] It is clear that the invention is not limited to just the above embodiment given as an example; on the contrary, it encompasses all of the possible variants of embodiment. Thus, the volume of air/volume of water ratio defined in the chamber (24) can be, for example, between 51/49 and 80/20, a small ratio of around 1 being ideal, however, in order to prevent the container (1) from having too great a height caused by the presence of the space (11) (FIGS. 1a and 1 b) or by that of the part (13) (FIGS. 3a and 3 b). 

1. Thermally self-insulating container (1), preferably a “bottle,” “flask,” “can,” or the like, designed to directly receive a product, preferably a food product such as a beverage, introduced or extracted, by means of an opening (5) closed by a cap (6), into or from an interior (4) delimited by an inner wall (2), said container also comprising an outer wall (3), which with the inner wall delimits a closed chamber (24), most of said inner wall (2) having a first state of high thermal conductibility and a second state of low thermal conductibility, said container being characterized in that it includes transformation means that are intrinsic to it, and mechanical control means (R, 12) for switching from said first state to said second state, in that, in the first state, the chamber (24) delimited by the double wall (2, 3) comprises a thermally conductive liquid (9) that fills at least the part of said chamber that is located level with the interior (4), and in that, in the second state, the chamber (24) delimited by the double wall (2, 3) contains a thermally insulating gas (10) that fills at least the part of said chamber that is located level with the interior (4).
 2. Self-insulating container according to claim 1, characterized in that the thermally conductive liquid (9) and the thermally insulating gas (10) present inside the double wall (2, 3) are water and air, respectively.
 3. Self-insulating container (1) according to either of claims 1 and 2, characterized in that the chamber (24) delimited by the double wall (2, 3): a) contains a first fluid (9) with high thermal conductibility and a second fluid (10) with low thermal conductibility, said first and second fluids (9, 10) having different volumetric masses and being non-miscible with one another, b) has a dissymmetry (11) such that, in a first position of the container (1) corresponding to the first state, most of the inner wall (2) is wet with the first fluid (9), and in a second position of the container corresponding to the second state, most of said inner wall (2) is wet with the second fluid (10).
 4. Thermally self-insulating container (1) according to claim 3, characterized in that the dissymmetry results from a space (11) between the part (23) of the outer wall (3) that constitutes the base of said container (1) and the part (22) of the inner wall (2) opposite this base, the volume of said space (11) being greater than 50% of the total volume of the chamber (24) delimited by the double wall (2, 3).
 5. Thermally self-insulating container (1) according to claim 4, characterized in that: a) the first fluid (9) is a liquid with high thermal conductibility, preferably water, and the second fluid (10) is a gas with low thermal conductibility, preferably air, b) the first position of the container corresponding to its first state is a first vertical position, the opening (5) or neck being headed downward, and the second position of the container corresponding to its second state is a second vertical position in which the opening (5) or neck is turned upward.
 6. Thermally self-insulating container (1) according to claim 3, characterized in that the dissymmetry results from a thickness (11) of the chamber (24) delimited by the double wall (2, 3) that is greater at the level of a part of the inner wall (2) constituting a side of the container (1) than it is at the level of the diametrically opposed part of the inner wall (2).
 7. Thermally self-insulating container (1) according to claim 6, characterized in that: a) the first fluid (9) is a liquid with high thermal conductibility, preferably water, and the second fluid (10) is a gas with low thermal conductivity, preferably air. b) the first position of the container corresponding to its first state is a first horizontal position in which the part of the chamber (24) delimited by the double wall (2, 3) having the greater thickness (11) is located at the top of the container (1), and the second position of the container corresponding to its second state is a second horizontal position in which the part of the chamber (24) delimited by the double wall (2, 3) having the greater thickness (11) is located at the bottom of said container (1).
 8. Self-insulating container (1) according to either of claims 1 and 2, characterized in that the transformation and mechanical control means comprise a breakable membrane (12) placed between the part of the outer wall (3) that constitutes the base (23) of said container (1) and the part (22) of the inner wall (2) opposite this base, and designed to release by gravity the overlying thermally conductive liquid (9), as well as a thermally insulating gas (10), preferably air, that fills the space (13) between said membrane (12) and the part of the outer wall (3) that constitutes the base (23) of the container (1).
 9. Self-insulating container (1) according to claim 8, characterized in that the mechanical control means comprise means for breaking the membrane (12), preferably by impact or by pressure.
 10. Self-insulating container according to any of claims 1 through 9, characterized in that the double wall (2, 3) is made of plastic or aluminum or any other material compatible with the product to be thermally insulated.
 11. Self-insulating container according to any of claims 1 through 10, characterized in that the first and second fluids (9, 10) are permanently introduced into the chamber (24) delimited by the double wall (2, 3) during the production of said container. 